Extensive research has shown that premature infants suffer impaired physical, social and cognitive development. The major focus of the proposed project is to facilitate their development through an intervention program of early stimulation. Such stimulation is now recognized as critical to normal development. To offset the relative "sensory deprivation" typically suffered in the isolette, intervention will begin shortly after birth and extend through out the premature's hospitalization (approximately 2 months). The intervention program will consist of daily periods of stimulation in the visual, tactual, and vestibular modalities. Its effectiveness will be assessed throughout the first-year of life by comparison with control groups on a variety of tasks. These assessments will focus on tasks which measure arousal level, visual attentiveness, social responsivity, and rate of mental development because there is evidence to suggest that these tasks are highly interrelated and sensitive to early experiences. Ages for testing have been worked out so as to allow comparisons between premature and full-term infants matched for both chronological and gestational age. The analyses will focus on (1) assessing the impact of sensory enrichment on development (2) determining whether any of the early behaviors predict later functioning and (3) answering questions having to do with the stability and inter-relationship of performance on the various measures. The tones are square-wave tones of 125 Hz and 400 Hz; presentation times are 20 sec. on -5 sec. off. The choice of stimuli and stimulus durations has been reached after extensive piloting. The response parameters recorded are: Heart rate, behavioral activity, and sucking. Current evidence concerning the ability of premature infants to habituate is scarce and contradictory. With full-term infants, on the other hand, the typical behavior is a waning of response to a repetitive series of stimuli. Whereas the initial orientation to a stimulus is biologically useful, continual alerting to a repetitive stimulus would make the infant a victim of irrelevant environmental variability. Rate of habituation is thus thought to be an index of behavioral placdicity. In the Arousal Procedure, the ease with which an infant is aroused is assessed by the length of time it takes him to initiate and continue crying after a pacifier is received. Four trails are used. We are interes (Text Truncated - Exceeds Capacity)